"Over the course of years and decades, burning more calories after every meal can make a significant difference in weight management," said study author Hana Kahleova from the Physicians Committee, U.S.
The study published in the journal JAMA Network Open assigned participants -- who were overweight and had no history of diabetes -- to an intervention or control group in 1:1 ratio.
For 16 weeks, participants in the intervention group followed a low-fat, plant-based diet which included fruits, vegetables, whole grains and legumes with no calorie limit.
The control group made no diet changes. Neither group changed exercise or medication routines unless directed by their personal doctors.
Researchers used indirect calorimetry to measure how many calories the participants burned after a standardised meal both at the beginning and end of the study.
The plant-based group increased after-meal calorie burn by 18.7 per cent on an average after 16 weeks. The control group's after-meal burn did not change significantly.
Within 16 weeks, participants in the plant-based group lowered their body weight by 6.4 kg (nearly 14 pounds), on an average, compared to an insignificant change in the control group.
The plant-based group also saw a significant drop in the fat mass and visceral fat volume -- the dangerous fat found around the internal organs.
The researchers teamed up with Yale University researchers to track intramyocellular lipid and hepatocellular lipid -- the accumulating fat in muscle and liver cells -- in a subset of participants using magnetic resonance spectroscopy.
Those in the plant-based group reduced the fat inside the liver and muscle cells by 34 per cent and 10 per cent, respectively, while the control group did not experience significant changes.
Fat stored in these cells has been linked to insulin resistance and Type-2 Diabetes, the researchers said.
The plant-based group also reduced total and low-density lipoprotein (LDL) cholesterol or bad cholesterol, with no significant changes in the control group.
"Not only did the plant-based group lose weight but they experienced cardiometabolic improvements that will reduce their risk to Type-2 Diabetes, heart disease and other health problems," the authors wrote.